#学习使用按位异或 ^ (0^0=0; 0^1=1; 1^0=1; 1^1=0)

if __name__ == '__main__':
    a = 12
    b = a ^ 3
    print(' a ^ 3 = %d' % b)
    b ^= 7
    print(' a ^ b = %d' % b)